As far as thanos, I don't see what's wrong with the guy who played him during the mid-credits scene. He might not be as tall as thanos' is (6'4 compared to 6'7) but put a couple inch lift in his boots and there's thanos, to me.

Sorry to critique so hard, and this isn't directed towards just you, but it boggles my mind why people want heights to match up exactly to comic book characters, especially ones that are taller than everyone else. You can't tell if someone is 6'7" by looking at them on the screen, or looking at them in a comic book. In fact, height is portrayed so inconsistently in comics it just boggles me why anyone would care about it when it comes to adaptations. The people who make the comics don't care about the height, we, as the audience, can't tell it by looking, how does it ever become a factor. He's taller than everyone else... how can adding four inches make the movie better? Or make him more faithful to the comics? Why is making the actor faithful to an arbitrary number in a superhero encyclopedia relevant? Would we be having this same complaint if he were 6'8" or 7'0" even? I just don't get it. [/rant]

Anyway, to respond to you personally, this is Damion Poitier, on of Whedon's go to big-guys from Firefly and Dollhouse. He played Sheriff Duprez on True Blood season 4 if anyone watches that. Maybe I'll look up his voice later. He doesn't really look like a soprano, though, y'know?